Leapfrog Sum Trick Worksheet
The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.
NameDateTime takenScore ___ / 40
- 1.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 2.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 3.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 5.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 8.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 9.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 10.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 11.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 12.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 13.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 14.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 15.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 16.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 17.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 18.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 22.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 23.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 24.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 27.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 29.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 30.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 31.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 32.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 33.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 34.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 36.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 37.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 38.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 39.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 40.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 715
- 935
- 561
- 1012
- 462
- 946
- 1232
- 704
- 374
- 231
- 671
- 198
- 319
- 880
- 891
- 847
- 924
- 473
- 1199
- 1177
- 550
- 759
- 583
- 770
- 407
- 660
- 715
- 759
- 737
- 649
- 1023
- 902
- 1287
- 880
- 484
- 539
- 1089
- 671
- 737
- 957
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